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| United States Patent |
5,212,728
|
|
Glover
, et al.
|
May 18, 1993
|
Dynamic trace elements
Abstract
The present invention relates to a dynamic hardware tracer for use in a
circuit. The circuit is comprised of real circuitry which performs a real
function and the tracer. The tracer is comprised of functional tracer
circuitry which receives input signals from the real circuitry and
processes the input signals. The functional tracer circuitry does not
interact with the real circuitry to contribute to or modify the real
function of the circuit. The dynamic hardware tracer provides an
indication of a copied circuit. The present invention also relates to a
dynamic software tracer located within a piece of software. The dynamic
tracer is comprised of at least one line of software tracer code imbedded
in a block of real software code. The at least one line of software tracer
code interacts with a tracer output signal from tracer circuitry located
in a circuit which also includes real circuitry which produces real output
signals providing a real function. The block of real software code
interacts with the real output signals. The software tracer does not
effect the operation of the real software, the real circuitry or the real
function. The software tracer provides an indication of copied software.
The piece of software need not interact with an integrated circuit, in
which case the dynamic tracer is comprised of a block of software tracer
code which is imbedded in and interacts with the block of real code but
which does not effect the running of the real code. Methods are also
provided for determining the origin of both hardware components and
software.
| Inventors:
|
Glover; Thomas E. (Ajax, CA);
Smith; Derek K. W. (Toronto, CA)
|
| Assignee:
|
International Business Machines Corporation (Armonk, NY)
|
| Appl. No.:
|
766607 |
| Filed:
|
September 26, 1991 |
Foreign Application Priority Data
| Current U.S. Class: |
705/58 |
| Intern'l Class: |
H04L 009/00 |
| Field of Search: |
380/3,4
365/228
364/184
|
References Cited
U.S. Patent Documents
| 4598170 | Jul., 1986 | Piosenka et al. | 380/4.
|
| 4813024 | Mar., 1989 | Lisimaque et al. | 380/4.
|
| 5027398 | Jun., 1991 | Miyoshi | 380/4.
|
Primary Examiner: Cangialosi; Salvatore
Attorney, Agent or Firm: Arnold; Jack M.
Claims
We claim:
1. A dynamic hardware tracer for use in first integrated circuit which is
comprised of a first circuit for generating at least one signal which is
indicative of performing a predetermined function, the hardware tracer
comprising:
a second circuit which performs a function independent of said first
circuit and does not interact with said first circuit to modify said
predetermined function of said first integrated circuit;
means for receiving and processing at least one input signal from said
first circuit; and
means for producing at least one detectable output signal from the
processed signal on at least one one detectable output terminal wherein
said output signal does not interact with the first circuit to modify the
predetermined function of the first integrated circuit, whereby said
dynamic hardware tracer, by its presence in at least one other integrated
circuit, provides an indication that said other integrated circuit has
been copied from said first integrated circuit.
2. The dynamic hardware tracer of claim 1 wherein said tracer circuitry is
formed as an integral part of the first circuit.
3. A first integrated circuit comprising:
first circuit which performs a predetermined function;
tracer circuitry means, connected to said first circuit, for electrically
processing at least one signal generated by said first circuit, said
tracer circuitry performing a function independent of said predetermined
function; and
means for producing at least one detectable output signal from said tracer
circuitry, wherein said at least one detectable output signal does not
modify said predetermined function of said first integrated circuit,
whereby said tracer circuitry means, by its presence in at least one other
integrated circuit, provides an indication that said other integrated
circuit has been copied from said first integrated circuit.
4. A dynamic tracer means including a computer, an integrated circuit, and
a dynamic software tracer located within a first software product running
on said computer wherein said first software product interacts with at
least one predetermined output signal produced by first circuit which
performs a predetermined function within said integrated circuit, the
dynamic software tracer comprising:
software tracer code means inbedded in said first software product, for
performing a dynamic tracer function independent of said first software
product and not affecting the operation of said first software product;
and
means, in said software tracer code means for interacting with at least one
tracer output signal from tracer circuitry in said integrated circuit
wherein said software tracer code means does not affect the operation of
said first software product or said function of said first circuit,
whereby said software tracer code means, by its presence in at least one
other software product, provides an indication that said other software
product has been copied from said first software product.
5. The dynamic tracer of claim 4, wherein said software tracer code means
interacts with said first software product to receive instructions from
said first software product, said software tracer code means performing
processing based on said instructions.
6. A dynamic tracer means including a computer, and a first software
product running on said computer comprising:
software code means for providing a predetermined function;
software tracer code means, imbedded in said software code means, for
performing a function independent of said software code means and not
affecting the operation of said first software product;
means, in said software tracer code means, for receiving and processing at
least one instruction from said software code means; and
means for producing from the processed instruction at least one traceable
output signal, which does not affect the operation of said software code
means, whereby said software tracer code means, by its presence in at
least one other software product provides an indication that said other
software product has been copied from said first software product.
7. A computing system comprising:
a computer means for running software means for detecting the presence of a
dynamic product tracer located within a product which is comprised of a
first portion which provides at least one predetermined output to perform
a predetermined function, and said dynamic product tracer comprised of
tracer means located within said product and interacting with said first
portion for providing at least one tracer output;
means for detecting the presence of said at least one tracer output in said
product; and
means for providing an indication of the presence of said at least one
tracer output to thereby detect the presence of said dynamic product
tracer, whereby said dynamic product tracer, by its presence in at least
one other product provides an indication that said at least one other
product has been copied from said software product.
8. The computing system claim 7, wherein said product is at least one
selected from the group of products comprising an integrated circuit, a
computer program, firmware and microcode.
9. A method of dynamically tracing the origin of an electronic hardware
component comprising the steps of:
(a) defining a first portion of said electronic hardware component which
performs a predetermined function;
(b) obtaining at least one output signal from said first portion;
(c) defining a second portion of said electronic hardware component which
is functional but which does not modify the operation of said first
portion;
(d) connecting said first portion to said second portion so that said
second portion operates on said at least one output signal to produce a
dynamic output signal; and
(e) detecting the existence of said dynamic tracer output signal to thereby
determine the presence, within the electronic hardware component, of said
second portion to thereby determine the origin of said electronic hardware
component.
10. A method of dynamically tracing the origin of a software product
comprising the steps of:
(a) running said software product on a computer,
(b) defining a first portion of said software product which performs a
predetermined function;
(c) obtaining at least one output from said first portion;
(d) defining a second portion of said software product which is functional
but which does not interact to modify the operation of said first portion;
(e) using said at least one output from said first portion to control said
second portion to produce from said second portion a dynamic tracer
output; and
(f) detecting said dynamic tracer output by means of said computer to
thereby detect the presence, within said software product, of said second
portion to thereby determine the origin of said software product.
Description
The present invention relates to a method and apparatus for detecting the
presence of one's copyright material in another's hardware and/or software
products or, in other words, tracing the origin of the material in
question. More particularly the present invention relates to a dynamic
tracing technique which can be implemented in both a hardware form, a
software form, or a combined hardware/software form.
BACKGROUND OF THE INVENTION
Prior art techniques have been developed for inserting static tracers into
software code so that it is possible to determine if a piece of software
has been copied or pirated. Prior art tracers are of a static nature in
that they are merely lines of code that do nothing and are ignored by the
program as it runs. However, these lines of do nothing code are in the
program code and if the code has been copied they will appear in the
copied version of the code and will be evidence of copying This is true,
because anyone who writes original code would not include the tracer in
the program code. If a person writing original code decided to insert a
tracer into a program, the chances of the tracer being the same code and
of it being located in the same position within the real code would be
extremely remote.
Those who copy software are becoming more sophisticated, and are
de-compiling the software which they wish to copy so that they can read it
and make subtle changes to it. The fact remains that the work is copied in
the main and constitutes an infringement of copyright in many
jurisdictions. However, since the sophisticated copier can read the code
he is about to copy he can find the static tracer code, since it does
nothing, and remove it from the program prior to copying. This is the
drawback of inserting a static tracer into program code.
In a similar manner, sophisticated hardware copiers are reverse engineering
micro chips or integrated circuits and using their knowledge of the
reverse engineered chip are making clones of that chip without having to
go through the expensive design and development stage.
DISCLOSURE OF THE INVENTION
The present invention is a technique for producing a type of dynamic tracer
operable in both hardware, software, or in a combination thereof.
A hardware tracer manifests itself as dynamic circuitry on a portion of an
integrated circuit or in discrete circuitry. This circuitry will be called
in this application "tracer circuitry". It is circuitry which is connected
to the rest of the circuitry of a product and which in fact may perform
some function, but that function has nothing to do with the actual
operation of the product. The remaining circuitry will be defined in this
application as "real circuitry".
This hardware tracer is defined as being dynamic in that is does function.
Not only does the tracer circuitry actually function but, it is connected
to the real circuitry and can take logic signals from the real circuitry
and process these signals to produce tracer output signals which can be
detected. The tracer output signals are not necessary for the operation of
the product. For example, if the product circuit is a video monitor driver
and contains tracer circuitry, the tracer circuitry and any signals which
the tracer circuitry produces are not used in the function of driving the
video monitor.
Since those, who reverse engineering a product in order to copy it, do not
go into the complicated and expensive process of determining how the
product's circuit operates, they can not distinguish the tracer circuitry
from the real circuitry and therefore will copy the tracer circuitry when
they copy the product's real circuit. If the circuitry were static or
passive it might become clearly obvious during the reverse engineering
operation and could then be blanked out in the copy.
The tracer circuitry can produce output signals which can be detected by
software. As a result, a detecting program can be written which probes for
these signals and displays some kind of indication of their presence. If
it is suspected that a piece of equipment contains a copied circuit, the
detection program can be run and if an indication of the presence of the
tracer signals ie present a good indication has been provided that the
product's circuit has been copied. This technique eliminates the need to
reverse engineer the suspected product circuit to determine if it is a
copy.
The invention contemplates building into software a dynamic tracer which
can be detected and which will provide evidence of copying.
Two embodiments of dynamic software tracers are provided by the present
invention.
The first embodiment is one where one or more lines of tracer code are
imbedded in lines of real code. The tracer software code interacts with
the tracer circuitry described above. Once again, the tracer software code
does nothing with respect to the running of the real software code, but
since it reacts with actual hardware, ie the tracer circuitry, a copier
who has dis-assembled the program will have considerable difficulty in
determining this fact, especially if several tracer "units" are dispersed
throughout the system. As a result, the copier is not likely to detect and
take the tracer code out of the program prior to copying and the tracer
will remain and thus provide evidence of copying.
One example of such a program is a diagnostic program used to check an
integrated circuit such as a video driver integrated circuit. This program
will be located in a ROM either on the mother board or the video card
itself. The program tests the integrated circuit by providing input
signals to the integrated circuit and by obtaining responses from the
integrated circuit. The real software code will test the real circuitry
and the tracer code, acting only as a dynamic tracer, will request
responses from the tracer circuitry. Anyone trying to determine the
operation of this program with the object in mind of copying the program
would have significant difficulty in determining the tracer code. The
copier would therefore be forced to leave the tracer code in the copied
program, thus preserving the tracer.
The second embodiment is one in which one or more lines of tracer code
interact with some lines of real code to produce results which are not
related to the operation or running of the real code. Since the tracer
code uses results derived from the real code and can even call up
sub-routines of real code, it is very difficult to detect as being tracer
code. As a result, a person even having disassembled the program will not
readily be able to determine if the tracer code is necessary and will
leave that code in the program, thus preserving the tracer.
One object of the present invention is to provide a dynamic hardware tracer
which is comprised of tracer circuitry which interacts with real circuitry
to produce tracer outputs which are present but which are not used in the
operation of the real circuitry.
Another object of the present invention is to provide dynamic hardware
detection software which can detect tracer signals generated by the tracer
circuitry to detect the presence of tracer circuitry.
Another object of the present invention is to provide a dynamic software
tracer which is comprised of software tracer code imbedded in real
software code which interacts with the tracer signals generated by the
tracer circuitry but which does not perform any useful function with
respect to the running of the real software.
It is yet another object of the present invention to provide a dynamic
software tracer which is comprised of software tracer code imbedded in
real software code which interacts with that real software code but which
performs a function which does not affect the running of the real
software.
In accordance with one aspect of the present invention there is provided a
dynamic hardware tracer for use in an integrated circuit which is
comprised of real circuitry which performs a real function, the tracer
being comprised of functional tracer circuitry which receives at least one
input signal from said real circuitry and processes said at least one
input signal, wherein said functional tracer circuitry does not interact
with the real circuitry to contribute to or modify the real function of
the integrated circuit, said dynamic hardware tracer, by its presence in
other integrated circuits, providing an indication that such other
integrated circuits have been copied from said integrated circuit.
In accordance with another aspect of the present invention there is
provided an integrated circuit comprising:
(a) real circuitry which operates to generate at least one output signal
which is output on at least one output terminal and which is used to
provide a real function; and
(b) tracer circuitry, connected to said real circuitry for electrically
processing at least one real signal generated by said real circuitry, said
tracer circuitry acting as a dynamic hardware tracer which interacts with
said real circuitry, said dynamic hardware tracer thereby providing an
indication by its presence in other integrated circuits that such other
integrated circuits had been copied.
In accordance with yet another aspect of the present invention there is
provided a dynamic software tracer located within a piece of software, the
dynamic tracer comprising at least one line of software tracer code
imbedded in a block of real software code, said at least one line of
software tracer code interacting with a tracer output signal output from
tracer circuitry located in an integrated circuit which also includes real
circuitry which produces at least one real output signal providing a real
function, said block of real software code interacting with said at least
one real output signal, wherein said software tracer code does not affect
the operation of the real software, the real circuitry or the real
function, said software tracer thereby providing an indication by its
presence in other software that such other software had been copied.
In accordance with still another aspect of the present invention there is
provided a piece of software including a dynamic software tracer, wherein
said piece of software is comprised of a block of real software code which
carries out processing to provide a real function; and at least one line
of software tracer code imbedded in said block of real software code, said
at least one line of software tracer code interacting with said block of
real software code to thereby receive instructions, said at least one line
of software tracer code carrying out processing based on said instructions
to produce a traceable result, said traceable result in no way affecting
the operation of the block of real software or the real function, said at
least one line of software tracer code thereby providing an indication by
its presence in other software that such other software had been copied.
In accordance with still another aspect of the present invention there is
provided a piece of software for detecting the presence of a dynamic
product tracer located within a product which product is comprised of real
portion providing at least one real output to thereby provide a real
function and a dynamic tracer portion comprised of tracer means located
within said product and interacting with said real portion for providing
at least one tracer output, said piece of software interacting with said
product to detect the presence of said at least one tracer output, and
displaying an indication of the presence of said at least one tracer
output to thereby detect the presence of said product tracer to provide an
indication by its presence in other products that such other products had
been copied.
In accordance with yet another aspect of the present invention there is
provided a method of tracing the origin of an electronic hardware
component comprising the steps of: defining a first portion of said
electronic hardware component which performs a specific useful function;
obtaining at least one output signal from said first portion; defining a
second portion of said electronic hardware component which is functional
but which does not contribute to the operation of said first portion;
connecting said first portion to said second portion so that said second
portion operates on said at least one output signal to produce a tracer
output signal; and detecting the existence of said tracer output signal to
thereby determine the presence, within the electronic hardware component,
of said second portion to thereby determine the origin of said electronic
hardware component.
In accordance with still another aspect of the present invention there is
provided a method of tracing the origin of a piece of software comprising
the steps of: defining a first portion of said piece of software which
performs a specific useful function; obtaining at least one output from
said first portion; defining a second portion of said piece of software
which is functional but which does not interact to modify the operation of
said first portion; using said at least one output from said first portion
to control said second portion to produce from said second portion a
tracer output; and detecting said tracer output to thereby detect the
presence, within said piece of software, of said second portion to thereby
determine the origin of said piece of software.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in detail hereinbelow with the aid
of the accompanying drawings, in which:
FIG. 1 is a block diagram of one aspect of the present invention;
FIG. 2 is a block diagram of one particular embodiment of the present
invention;
FIG. 3 is a schematic diagram of relevant parts of the embodiment shown in
FIG. 2;
FIG. 4 (appearing on the same sheet of drawings as FIG. 1) is a
continuation of the schematic diagram of FIG. 3;
FIG. 5 is a diagram of a portion of a software listing showing one
embodiment of the present invention;
FIG. 6 is a diagram of a portion of a software listing showing another
embodiment of the present invention, and
FIG. 7 is an example of a software listing which will detect the presence
of a dynamic hardware tracer of the present invention.
BEST MODE OF CARRYING OUT OF THE INVENTION
FIG. 1 shows a first embodiment of the present invention. An integrated
circuit 10 includes a portion of real circuitry 12 and a portion of tracer
circuitry 14. The real circuitry can be of any type and perform any
function. The tracer circuitry is operational circuitry that functions to
provide output signals at terminals 16 and receives signals from the real
circuitry via input terminals 20. However, the tracer circuitry does not
have anything to do with the actual functioning of the integrated circuit.
For example if the integrated circuit performs the function of driving a
video monitor, the real circuitry 12 performs all of the necessary
functions to drive the video monitor. The tracer circuitry acts as a
tracer so that if the integrated circuit 10 is reverse engineered with the
intent in mind to slightly modify it and copy it, a dynamic tracer will
remain in the copied integrated circuit which will be evidence of the fact
that the integrated circuit was copied. When the copier reverse engineers
the integrated circuit, the result will be scrutinized with the intent of
modifying or removing some trivial portion in order to mask the fact that
the integrated circuit has been copied. If the tracer circuitry was merely
static, in that it did not interact with the real circuitry, or did not
produce an output of some kind, it would be much easier to detect and
remove. It is extremely difficult to distinguish the dynamic tracer
circuitry of the present invention from the real circuitry and so it is
not likely that a copier would be able to remove it and have confidence
that the modified copied integrated circuit would function properly.
The arrangement shown in FIG. 1 can optionally interact with software which
also contains a dynamic tracer. A series of software coding 22 contains
portions of real software coding 24 and tracer software coding 26. The
real software coding 24 interacts in a normal fashion with the real
circuitry 12. Such interactions are shown schematically in FIG. 1 by links
28. The tracer software can interact via link 30 to the tracer circuitry
14. The real software can also send instructions to the tracer software by
a link 32. It should be noted that the tracer software does not produce a
result or interact with the real software in such a way as to produce a
result that is used either by the real software or the real circuitry. As
a result, a dynamic tracer is present in the software. A copier when
studying the dis-assembled software in an attempt to slightly change the
software for the purposes of copying, would not remove the dynamic
software tracer because the tracer software appears to legitimately
interact with the integrated circuit and/or the real software. The copier
could not remove the tracer software for fear of making the resulting copy
inoperative. The software tracer therefore becomes a tracer and provides
evidence that the software has been copied.
FIG. 2 is a block diagram of a video monitor and printer driver circuit
which has been modified to include tracer circuitry according to the
present invention.
The circuit shown in FIG. 2 can be considered to be a bread-board mock-up
of an integrated circuit.
It is not necessary for an understanding of the invention to go into a
great deal of detail concerning the circuit shown in FIG. 2.
This circuit can be connected to the main bus of a mother-board in a
computer. Table 1 shows the relationship between various addresses on that
bus and the functions which they represent.
TABLE 1
______________________________________
I/O
Address on Bus Function
______________________________________
3B0 Not Used
3B1 Not Used
3B2 Not Used
3B3 Not Used
3B4 6845 Index Register
3B5 6845 Data Register
3B6 Not Used
3B7 Not Used
3B8 CRT Control Port 1
3B9 Reserved
3BA CRT Status Port
3BB Reserved
3BC Parallel Data Port
3BD Printer Status Port
3BE Printer Control Port
3BF Not Used
______________________________________
It can be seen from table 1 that there are several address locations on the
bus that are not used. These unused locations can be used for tracer
signals and represent the terminals 16 shown in FIG. 1. As a result, it
can be seen that the architecture of the bread-board and its interaction
with its outside world does not have to be changed to any great degree to
implement this invention. This is true in most cases because it seldom
occurs that a device will use up all the available ports and their
associated addresses for the actual operation of the device.
In this example, addresses 3B0, 3B1 and 3BF, which are not used in the real
circuitry are utilized in the tracer circuitry to produce a Screen Column
Port, a Screen Row Port, and a Screen Active Port, respectively. In other
words, tracer circuitry will be developed which will take signals from the
real circuitry and produce tracer signals representing the cursor position
on the video monitor with respect to column and row, and a signal
representative of the Screen being active or inactive.
The tracer circuitry will be located in video support logic block 34 of
FIG. 2.
FIGS. 3 and 4 are a more detailed schematic drawing of the video support
logic shown in block 34.
The tracer circuitry added to block 34 produces the Bit Number/Function
charts shown in tables 2, 3 and 4.
TABLE 2
______________________________________
Screen Column Port
Bit # Function
______________________________________
0 .sub.--
1 .sub.--
2 .sub.--
3 .sub.-- Col Pos
4 .sub.--
5 .sub.--
6 .sub.--
7 1 Enable
0 Disable
______________________________________
TABLE 3
______________________________________
Screen Row Port
Bit # Function
______________________________________
0 .sub.--
1 .sub.--
2 .sub.--Row Pos
3 .sub.--
4 .sub.--
5 1 .sub.--
0 .sub.-- Active Pg
6 1 .sub.-- (1 of 4)
0 .sub.--
7 1 Enable
0 Disable
______________________________________
TABLE 4
______________________________________
Screen Active Port
Bit # Function
______________________________________
0 .sub.-- Resolution
1 .sub.-- (1 of 4)
2 1 Enable Blink
0 Disable Blink
3 1 Enable Video
0 Disable Video
4 1 Update Active
0 Update Complete
6 Reserved
7
______________________________________
Existing decoder 31 produced a signal at output terminal 38 which is
normally not used. This signal is the Screen Active Port Select signal or
SAP SEL signal and is fed to decoder 40 shown in FIG. 4. This signal, in
conjunction with a timing signal which is inverted by inverter 42 controls
the decoder 40 to decode the data appearing on the data in lines to
produce the various bit-functions on the data out lines. The decoded
signals appearing on the data out lines follow the bit pattern shown in
table 4.
Referring again to FIG. 3, an inverter 44 feeds an existing signal from the
real circuitry to decoder 46. This signal, in conjunction with the
existing signals appearing on lines 48 and 50 controls the decoder 46 so
that existing signals appearing on lines 52, 54 and 56 are decoded to
produce a Screen Column Port Select signal SCP SEL and a Screen Row Port
Select signal SRP SEL on output terminals 58 and 60, respectively.
The SCP SEL signal is fed to decoder 62 shown in FIG. 4 and, taken in
conjunction with the timing signal inverted by inverter 64, produces the
bit pattern shown in table 2 on data out lines from signals appearing on
data in lines for that decoder.
The SRP SEL signal is fed to decoder 66 shown in FIG. 4 and, taken in
conjunction with the timing signal inverted by inverter 68, produces the
bit pattern shown in table 3 on data out lines from signals appearing on
data in lines for that decoder.
The tracer circuitry added to the real circuitry of the integrated circuit
consists of inverters 42, 44, 64, and 68 and decoders 40, 46, 62 and 66.
It must be understood that this tracer circuitry forms only a very small
part of the total real circuitry of the integrated circuit. Furthermore,
it should be understood that the circuitry shown is merely an example of
the invention and the invention is in no way limited to the circuitry
shown.
FIG. 5 is a portion of a software code listing which checks the circuitry
of the video monitor and printer driver shown in FIG. 2 and the circuitry
of the tracer circuitry added and shown in FIGS. 3 and 4. Prior to
operation, at each start-up or boot of a computer having such a video
monitor and printer driver, a program stored in a ROM located on the
mother-board is run which is known as a diagnostic program. It is the
function of this program to check the various functions of the video
monitor and printer driver integrated circuit to insure proper operation
of that circuit.
FIG. 5 includes blocks of real software 70 and a block of software tracer
72 imbedded in the real software. The real software checks the real
circuitry of the integrated circuit. It is critical to the operation of
the computer that the diagnostic checks be correct on this portion of the
circuitry. The tracer software interacts with the tracer circuitry to
check that circuitry. Since the operation of the tracer circuitry has
nothing whatever to do with the operation of the actual integrated
circuit, the fact that there are diagnostic results of the tracer
circuitry derived from the operation of the tracer software is irrelevant.
What is not irrelevant is the existence of the tracer circuitry and
software in both the integrated circuit and the software program. Their
existence provides the dynamic hardware tracer and dynamic software tracer
of the present invention.
It is not necessary, according to the present invention that the software
tracer have actual hardware with which to interact. A dynamic software
tracer can exist without interaction with hardware as long as the software
tracer has real software with which to interact. FIG. 6, is an example of
such software. In this example, blocks of real software coding 74 interact
with blocks of software tracer coding 76 to provide the dynamic tracer. It
should be noted that the tracer software 76 receives and processes data
from the real software 74. However, the results of the processing of this
tracer data is not used in the operation of the real software. If the
software tracer was used, it would not fulfil its function as a tracer
because it would no longer be tracer software.
In the past, if one suspected that an integrated circuit was copied, it was
necessary, from the outset, to reverse engineer the suspected circuit in
order to try to find similarities with the original circuit in order to
provide evidence of copying. This operation is costly.
Since, as is shown in FIG. 1, the tracer circuitry 14 produces signal
outputs on output terminals 16, these signals can be detected. Software,
i.e. software similar to the software tracer 26 shown in FIG. 1 can be
provided for detecting and displaying an indication of the presence of the
tracer signals generated by the tracer circuitry. That software can
therefore detect the presence of the tracer circuitry, because if the
signals exist, so must the circuitry.
Running this tracer circuitry detection software on an integrated circuit
suspected of being copied is much less expensive than reverse engineering
the suspected integrated circuit at the outset.
An example of this software is shown in FIG. 7 and is a piece of software
which tests the diagnostics of only the tracer circuitry shown in FIG. 2.
This software provides an indication of the presence of tracer signals
generated by tracer circuitry and is therefore an indicator of the
existence of tracer circuitry in an integrated circuit under test. This
software is an example of tracer circuitry detection software. It is very
similar to the block of software tracer shown in FIG. 5, but it does
produce a useful output, namely an indication of the existence of the
tracer signals discussed above.
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